River Macrophytes Database

Citation

Description

The River Macrophytes Database (RMD) is a Microsoft Access database constructed to house data on the plant communities of rivers in Great Britain and Northern Ireland. It includes data from over 7000 survey sites and is the most comprehensive database of its kind. Data have been collected from all over the UK between 1977 and the present day, following the methods of Holmes et al. (1999).
The data held in the RMD are the result of collaborative work across all four statutory nature conservation bodies: Scottish Natural Heritage (SNH), Natural England (NE), Natural Resources Wales (NRW, formerly CCW) and the Northern Ireland Environment Agency (NIEA).

Purpose

These records were collated following the first comprehensive national survey of macrophytes in rivers throughout Britain. This was commissioned by the Nature Conservancy Council between 1978 and 1982. A significant number of new surveys have been added subsequently to fill gaps in geographical coverage and store data from re-surveys of the original sites. The collection of data allowed a comprehensive national rivers classification (based upon macrophytes) to be developed. The latest version of this classification system is published in, a^??Holmes, N.T, Boon, P.J. & Rowell, T.A., (1999), Vegetation communities of British rivers - a revised classificationa^??, and is available online at: http://jncc.defra.gov.uk/page-2619.

Sampling Description

Quality Control

Confidence in the data = high. All surveys were collated by very experienced and qualified specialists in the field of aquatic macrophytes. Much of the data were collated from one or two large survey programmes and so data processing and validation were standardised and consistent throughout. More recent data have been input by a standardised data capture field form, thus minimising the possibility of introducing any errors during the data input process.

Method steps

The macrophyte survey method records aquatic and marginal plants in a 500m long survey section of river. Species from the river channel and the margins/base of the bank are recorded separately on a three-point scale of relative abundance and percentage cover. A standard check-list of species is used to aid recording. The field data can be used to classify the plant community as described by Holmes et al. (1999), and the database has a facility that allows keying-out of the community to sub-type level. This plant community classification has been used as the basis of river SSSI selection. The database also holds a small amount of invertebrate and fish data.
The grid reference of the species observation is the lower grid reference of the river section (the upper grid reference included as an attribute) and the precision of the record provided reflects this lower grid reference rather than the 500m long survey section.